Rubber composition and method of preserving rubber



Patented Dec. 16, 1930 B -PAT:

PAUL C. JONES, 0F GUYAHOGA FALLS, OI-IIO ASSIGLN'O 7 rANY, or NEW YORK,'N.Y., A coaroanrronio'r NEW YORK" RUBBER: COMPOSITION'AND METHOD or ranssavrne RUBBER No Drawing. Originalapplication fi led January 21, 1929,:Seria1tNo 33 g121 d fiividedand this appliedtion filed December 14, 1929. Serial Ne..414,2a1.

This inventionrelates to the art of preserving rubber, either in a vulcanized or unvu lcanized condltion, and to rubber compositions so preserved.

It is well known that rubber gradually loses its strength and'resiliency onaging, especially when exposed to light, airor heat, and that many reducing substances, such as organic nitrogen ,compo'unds, possess the property of retarding this deterioration, Among such compounds which have been employed with more or less success as age-resisters or anti-oxidants to retard the deter10ration of rubber arezaniline, p-amino-phenol, acetaldehyde-aniline, ethylaniline, and phenylhydrazine.

This invention, in brief, consists in treating rubber with a substance belonging. to a new class of age-resisters,comprising tetra-substituted hydrazines. These compounds, when incorporated into rubber before vulcanization, preferably from 0.1% to 5% of the age-resister-being used, are far more eiiective in retarding the deterioration of rubber than the previously known substances mentioned above.

.The tetra-aryl hydrazines in general may be prepared by the controlled oxidationof secondary aromatic amines. For example, it the theoretical amountofpotassium perinanganate in acetonesolution is added toa sol'u tion of diphenylamine in acetone, the diphenylamine is oxidizedto tetraphenyl hydrazine v V a tire tread composi-tmn was prepared containing: blended plantation rubbers 10 0 parts by weight, sulfur 5.5 parts, zinc oxide according to the following equation:

The manganese dioxide which is formed simultaneously is filtered off and the acetone evaporated. If desired the crude product maybe recrystallized from alcohol. The

pure tetraphenyl hydrazine is a colorless crystalline substance, but the crude product is a more or less strongly colored pasty mass.

action product, since the by-produc'ts of the or are: substantially inert. They" have the effect of lowering-the melting point andiincreasing the solubilityof the material in rubber, whichis sometimes a considerable ad-- vantage. p a I Other tetra-substituted hydrazines, such as tetra-benzyl hydrazine, tetra-tolyl hydrazine, tetra-hydroxy tetra-phenyl hydrazines, tetrachlorphenyl hydrazine, nyl) hydrazine, dihydroxy tetra-.phenyl hydrazine, di-hydroxyphenyl ditolyl hydrazine, diphenyl ditolyl' hydrazine, dianisyl diphenylhy'drazine, etc, may be prepared in a. similar manner and likewise are very'active age-resisters. When the aryl groups aresubstood that the method of preparing the tetra substituted hydrazinesv is immaterial, such products in general being excellent'age-resisters in rubber. V

Example 1. As a specific example of one tetrap-ami-nophe- V ago THE B. r. Goonson 00M, v

embodiment of the method of; this invention,

30 parts, gas black 40 parts, mineral rubber 10 parts, palm oil 5 parts, and hexamethylene tetramine 0.75 parts. This was divided into an optimum cure. The relative rates of aging p of the vulcanized. compositions were com- It is not always necessary to purlfy'the repared by measuring their respective tensile strengths and elongations before and after h aging. Accelerated aging tests were carried The compositions two portions, one of which was used as a .90

out in the Greer aging oven, in which samples were maintained at a temperature of 158 F.,

in a constantly renewed stream of air, as well as in the Bierer-Davis bomb, in which other samples were maintained at the same tem perature (158 11) in an atmosphere of oxygen at a pressure of 300 lbs. per s'qu'in; In

the table'below T indicates ultimate tensile strength in pounds per square inchand E indicates ultimate elongation in per cent. of i original length. p

- Aging tests of tetraphenyl hydma ine After 48' Before}' {gag &3 hours in the' aging oven Bierer- Age-resistor (0.5%) ws 'r l E "r E r' E None(control) 3607 as 1976 493: 804 357 Tetraphenyl hydrazine 3718 733 3389 580 27 1 1 630 "After 48 7 Before g i g gg hours in the aging oven Bierer- Age-resister(0.'5%) Davis bomb T E v T E T E None (control) 3540 663 2196 i 470' 642: 263 Tetrabenzyl hydrazinenfln' 3405 670 2549 550 2089 567 Example 3.- N,N-di-p-anisy1-N,N@diphe,

nyl hydrazine,

also exhibits remarkable anti-oXident powers in rubber, asis evident from thefollowing table:

Aging tests of dianisyl diph eni l hydrazine i After 48 Before g g g gf hours in,the I aging oven Bierer- Age-resister (0.5%) Davls bomb '1 E T E T, E

None (control) 3540 663' 2196 "470 642 263 Dianisyl diphenyl hydrazine 3303 663 3150 577 2564 I 573 Example .4.'The effect of the tetra-substituted 'hydrazines is most marked when all four subst tuent groups comprise, p su'bstituted benzene nuclei. For example, tetra-ptolyl hydrazine,

' gives the following results I After 48 Before f g gfi hours in the aging oven B erer- Age-resister(p,5%) I Dav s bomb 'i E 'r 'E 'r E None (controDi' 34513 640 2008 417 642 263 Tetra-p-tolyl hydrazine.--" 3554 697 .3262 570 .2723 J 607.

From the above data it is evident-that the tetra-substituted hydrazines are excellent age-resisters in rubber. The tetra-aryl hy-v dra-zines, in particular, are-soactive as ageres sters that aycom-position contalnlng only 1 0.5% undergoes substantially no deterioration when'subjected to an accelerated aging test'which almost completely destroys the strength of the same composition without the tetra-aryl hydrazine. However, it is to s be understood that theexamples are merely illustrative, and that the tetra-substituted hydrazinesmay be incorporated into 'rubber compositions of the most various nature with good effect upon their age-resisting properties. They may also be applied to unvuh or in the form of a paste or emulsion; It is to be understood that the term ing as employed in the appended claims is rubber by milling or [similar process, or their surface of a mass of crude or vulcanized rubber. The term rubber istlikewise ,em

ployed in theclaims in avgeneric senseto in clude caoutchouc,. whether "natural or synthetic, ,.reclaimed-' rubber, Hbalata, gutta percha, rubber isomersrand like products,

whether or notadmixedwith fillers, pigments,'-vulcaniz1ng or accelerating agents.

., This lapplicationis a division o-f my copending application, Serial No, 334,121, filed January 21, 1929., v I 7 While I have herein disclosed certain preferred manners of performing my invention, I

I donot thereby desire or intend to limit my self solely thereto, for, as hitherto stated,

the precise proportions ofthe materials uti-' lized may be varied and other materials having equivalent chemical properties may be 7 A y in g tests-of tetfap toi gjl Mam-me" canizedor vulcanized rubber-with good ef-"'- fect "on the age-resisting properties of the rubber, such as by applyingthemto-the surface of the rubber, as for example in solution,

treat used in a generic sense to-include either the I p incorporation of the age-resisters into the Q addition to the rubber latex before its coagu-- v 1 lation, orto-the application thereof. to the;

employed if desired without departing from V the spirit and scope of the invention as defined in the appended claims.

I claim: 1. The method of preserving rubber which comprises treating rubber with a tetra-aryl hydrazine in which at least one of the aryl groups is substituted.

2. The method of preserving rubber which comprises treating rubber with a tetra-aryl hydrazine in which at least one of the aryl groups is substituted in the para' position.

3. The method of preserving rubber which comprises treating rubber with a substituted tetra-aryl hydrazine in which the substituents are substantially neutral character. 1

4:. The method of preserving rubber which i comprises treating rubber with an alkoxy substituted tetra-aryl hydrazine.

5. The method of preserving rubber which comprises treating rubber with an alkoxy substituted tetra-arylhydrazine, the alkoxy groups being located in the para position.

6. The method of preserving rubber whichdi-p comprises treating rubber with N, N anisyl N, Ni diphenyl hydrazine.

7. The method of manufacturing an ageresisting rubber product which comprises incorporating a substituted tetra-aryl hydrazine into a vulcanizable rubber composition,

and vulcanizing the composition.

8. An age-resisting rubber composition comprising rubber and a substituted tetraaryl hydrazine.

9. An age-resisting rubber composition comprising rubber and a para substituted tetra-aryl hydrazine.

10. An age-resisting rubber composition comprising rubber and a substituted tetraaryl hydrazine in which the substituents are substantially neutral in character. a

11. An age-resisting rubber composition comprising rubber and an alkoxy substituted tetra-aryl hydrazine.

12. An age-resisting rubber composition comprising rubber and an alkoxy substituted tetra-aryl hydrazine in which the alkoxy groups occupy the para-position.

13. An age-resisting rubber composition para substituted-tetra-aryl organic V 

